76 , BYZANTINE CHURCHES CHAP. marbles/ says Procopius,1 c it was more resplendent than the sun, and everywhere It was filled profusely with gold.' When Ferguson examined the building, remains of frescoes or of mosaics, which have disappeared since his time, could be distinguished in the narthex. The soffit, both of the upper and of the lower cymatium on the piers, projects sufficiently to admit the application of the customary marble Incrustation. The proportions of the building are marred by the boarded floor which rises seventeen centimeters above the original pavement, disguising the real elevation of the dome and of the columns in the lower colonnade. But notwithstanding all changes for the worse the building is still a beautiful structure. Very effective especially is the happy combination of the various lines and forms here brought together—the rectilinear and the semicircular sides of the octagon, the octagonal fabric and the round dome that crowns it, the horizontal entablature stretched along the summit of the lower story of columns and the arches that leap from column to column in the gallery. This harmonious variety of form has also a historical significance. An old order in architecture and a new order here meet and embrace before the earlier, having served its age, passes away and the later comes triumphant to fill another era of the world with fresh beauties. Here in the tide of time we look before and after. To the student of architecture the dome of this church is specially Interesting. In the application of the dome to the octagon no pendentives are employed. The octagon is carried up to the base of the dome, which is built In sixteen longitudinal compartments that impinge upon one another and form groins giving to the dome its strength and sweep. On the groins is a plaster moulding, probably Byzantine. The eight compartments directly above the dome arches are flat, and flush with the inner face of the octagon, and in each of them is a semicircular-headed window. They rise perpendicular to a point a little above the windows, and then curve with a radius to the centre of the dome. On the other hand the eight compartments directly above the angles of the octagon are narrower than the preceding 1 De aed.i. p. 187.